Shmuel Assouline

Raindrop‐induced soil surface sealing alters infiltration, runoff, and sediment detachment, yet most erosion models fail to capture its dynamic impacts on interrill processes at event scales. Conceptually informed by the process‐based approach of Water Erosion Prediction Project, we develop a modeling framework that couples seal formation, two‐layer infiltration, kinematic wave overland flow, and interrill erosion. The framework integrates slope gradient and rainfall intensity into the temporal evolution of interrill erodibility, enabling explicit representation of sealing dynamics. Laboratory data of Assouline and Ben‐Hur (2006, https://doi.org/10.1016/j.catena.2006.02.005 ) covering rainfall intensities of 24–60 mm hr ⁻¹ and slopes of 5%–25%, were used for evaluation. The model reproduced observed sediment loads with normalized RMSE of 14%–20% and Nash‐Sutcliffe efficiencies of 0.70–0.89, outperforming the version in which the progressive sealing effect is omitted. Results highlight two competing sealing effects: reduced interrill erodibility suppresses detachment, while increased rainfall excess enhances transport capacity. Their relative importance depends on slope: increasing rainfall excess dominates erosion on gentle slopes, whereas interrill erodibility reduction controls erosion on steep slopes. The model also reveals dynamic regime shifts from transport‐limited to transitional or detachment‐limited during sealing. Comparisons show that neglecting seal formation can substantially underestimate sediment loads, whereas assuming instantaneous sealing overestimates erosion by 37%–71% on gentle slopes and underestimates it by 2%–7% on steep slopes. By resolving slope‐ and rainfall‐dependent sealing dynamics, the proposed model provides a physically based framework for event‐scale interrill erosion prediction, improving the reliability of rainfall‐runoff‐erosion assessments in erosion‐prone landscapes.

In ecophysiology leaves are frequently stored for hours after sampling before measuring their leaf water potential (Ψ_leaf). Here, we address a previously unidentified source of error, that metabolic heat generation can cause continuous water loss from leaves stored in impermeable bags, leading to a Ψ_leaf drop over time. We tested Ψ_leaf drop rates under various conditions: two bag materials, two species, initial Ψ_leaf above or below the turgor loss point (Ψ_tlp), and storage at 25°C versus 4°C. We partitioned leaf water loss due to condensation on the inner bag surface or permeation through the bag. We found that Ψ_leaf dropped by up to 0.39 MPa per hour, with 41%–89% of the water leaving the leaf condensed on the inner bag surface. Plastic bags showed higher Ψ_leaf drop rates than aluminium bags, and leaves above Ψ_tlp experienced greater drops. Storing leaves at 4°C reduced the Ψ_leaf drop rate by 60% compared to 25°C. Leaves were 0.2–0.3°C warmer than the bags, likely due to metabolic heating. Our energy balance model suggests that water loss is lower when storing leaves at cooler temperatures, using leaves with low stomatal conductance, deflated bags, and leaves with low Ψ_leaf.